1024MAK wrote: ↑Mon Nov 13, 2017 1:30 pm
As for your existing fan, if you have some rubber O rings of a suitable size, you could use these. That is what is used on some computer fan mounting kits.
But note that O rings are normally used between the fan and the bolts/screws that are used to fit the fan to the enclosure/case or heatsink...
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
Lardo Boffin wrote: ↑Mon Nov 13, 2017 1:24 pm
For the electronically minded - if we reduce the voltage to the fan will it just reduce the speed a little?
I am wondering whether there will be a good tradeoff between speed (and noise) and cooling ability?
Short answer, normally yes. Either use a suitable resistor or use a lower supply voltage.
Long answer, not always, due to the "motor" being a brushless type. Inside, there is an electronic circuit, which switches each coil on and off in a sequence, this causes a permanent magnet to try to follow the magnetic field generated by each coil. So the resistor cannot be too high a value/the supply voltage cannot be too low, otherwise the magnetic field strength from the coils will be too low to attract the permanent magnet...
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
I have some silicone washers which are the right size just no bolts narrow enough. The smallest I have is m3.5 but I need m3.
A gasket type approach would be good but I can’t find any that are anywhere near small enough.
Does anyone know of any good brand of cooling fans? That are this small.. The one I have is 25 by 25 by 10mm. I think 7.5mm would be better given the clearance and additional height taken up by the vibration damping.
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
Rather than faff around with resistors or making the job more complicated than it needs to be just use a 12v fan tapped off 9v.
I have done this on a Fuller cased zeddy result adequate air movement and near silent running, the fan doesn't need to running at 10,000 rpm to shift enough air.
Cheap/small fans by nature are badly balanced and this is exaggerated when run at full speed as I've said before a gentle throughput is all that's required not a hurricane.
Moggy wrote: ↑Mon Nov 13, 2017 2:58 pm
Rather than faff around with resistors or making the job more complicated than it needs to be just use a 12v fan tapped off 9v.
I have done this on a Fuller cased zeddy result adequate air movement and near silent running, the fan doesn't need to running at 10,000 rpm to shift enough air.
Cheap/small fans by nature are badly balanced and this is exaggerated when run at full speed as I've said before a gentle throughput is all that's required not a hurricane.
Thanks. Do you know any good quality 12v fans that are ideally 25 by 25 by 7.5 or failing that 25 by 25 by 10? I guess we could go to 40 by 40 by 10 with a little surgery...
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
Moggy wrote: ↑Mon Nov 13, 2017 2:58 pm
Rather than faff around with resistors or making the job more complicated than it needs to be just use a 12v fan tapped off 9v.
I have done this on a Fuller cased zeddy result adequate air movement and near silent running, the fan doesn't need to running at 10,000 rpm to shift enough air.
Cheap/small fans by nature are badly balanced and this is exaggerated when run at full speed as I've said before a gentle throughput is all that's required not a hurricane.
Thanks. Do you know any good quality 12v fans that are ideally 25 by 25 by 7.5 or failing that 25 by 25 by 10? I guess we could go to 40 by 40 by 10 with a little surgery...
Just nipped into attic and removed a chipset fan of the same dimensions as yours,Lardo, and quickly wired it up to the 9v on my test 81 with xpand and zonx box connected and at 9v running I was surprised to find it still a tad noisy but at 5v really quiet and still a good airflow so will continue this evening to fit to a normal zeddy and post results.
As for suppliers I will continue searching this afternoon (forget Farnell silly money) then report back.
I forgot to say earlier that after 3 hours of running The Gauntlet I opened up the case and quickly did the highly technical finger temperature test.
I believe that just too hot to touch is around 60 degrees C and it was only pleasantly warm to the touch so still nice and cool.
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA